IsometricScreenToMap

        public Vector2 ScreenToMap(Vector2 source)
        {
            switch (CameraDirection)
            {
                case FaceDirection.NorthWest:
                    return new Vector2((source.X / GameConstants.CellHalfWidth + source.Y / GameConstants.CellHalfHeight) / 2.0f,
                        (source.Y / GameConstants.CellHalfHeight - source.X / GameConstants.CellHalfWidth) / 2.0f);
                case FaceDirection.EastNorth:
                    return new Vector2((source.Y / GameConstants.CellHalfHeight - source.X / GameConstants.CellHalfWidth) / 2.0f,
                        (source.Y / GameConstants.CellHalfHeight + source.X / GameConstants.CellHalfWidth) / 2.0f);

                case FaceDirection.SouthEast:
                    return new Vector2((source.Y / GameConstants.CellHalfHeight + source.X / GameConstants.CellHalfWidth) / 2.0f,
                        -(source.Y / GameConstants.CellHalfHeight - source.X / GameConstants.CellHalfWidth) / 2.0f);

                case FaceDirection.WestSouth:
                    return new Vector2(-(source.X / GameConstants.CellHalfWidth - source.Y / GameConstants.CellHalfHeight) / 2.0f,
                        (source.Y / GameConstants.CellHalfHeight + source.X / GameConstants.CellHalfWidth) / 2.0f);
            }
        }